Officials say a rare infection at Greenville Memorial Hospital may have been a factor in the deaths of three patients.

Fifteen patients have tested positive for the infection linked to surgical equipment.

All three patients who died also suffered from other serious health conditions, said Greenville Health System medical quality director Dr. Robert Mobley Jr.

“Our thoughts are with those involved. Our ongoing priority will be to monitor these and other patients for continued safe and effective care,” Mobley said.

Officials said June 20 that 14 patients tested positive for atypical Mycobacterium abscessus. Most of them had cardiac surgery, while two had abdominal surgery and one a neurological operation.

Another case was confirmed last week. The first patient recognized with the infection tested positive in March.

Part of the problem is the long incubation period for the bacteria, with some patients having no sign of infection until months after an operation.

Six of the patients are being treated at home, while the other six are in the hospital or are being treated at another long-term care facility.

A piece of surgical equipment has been implicated in the infection, but the investigation into the source of the bacteria includes the U.S. Centers for Disease Control and Prevention and the Department of Health and Environmental Control.

The equipment was removed and the operating room was closed temporarily, officials said. They hope to re-open it in a few weeks.